Despite the spin, Brittan is no longer a multicultural society. When, in the early 50s, Britain went from being the biggest exporter of man power to the biggest importer in the world it started to go wrong. As manpower was moved into the areas where workers were needed most segregation began. In the early day it did not matter so much, most immigrants were from the Empire and where proud of it. Now the Empire is long gone, there is no pride in being 'British' and communities are divided into cultures, religions and nationalities.
Couple this with all the PC garbage, another throw back to the Empire. Gone is the 'white mans burden' and the 'noble savage' attitudes of the past. Forcing a certain way of life on people is now seen as pure evil, mainly out of perceived guilt. Civil liberties, freedom of speech, human rights and many other legal aspects have come into place. These laws/rules allow people to chose there path in life, but who is to say they will chose correctly? There is nothing wrong with expecting (or even forcing) certain standards from people as long as it is one rule for all.
On the subject of immigration, ask yourself why Britain has so many immigrants. Part of it is because we have plenty of (by UK standards) low paid jobs and not enough people are doing them. People know they can make plenty of money with allowances and benefits, why pick strawberries all day? As Sir Humphrey Appleby once said "This country will have as much unemployment as it is prepared to pay for".
If you are happy to pay 20+ pence a kg more for strawberries (and more for all the other products from low paid jobs) then you can complain about immigrants. If you want cheap produce, except why it is cheap and shut up (or do something constructive about it).